1. Field of the Invention
The present invention relates to flashing and sealing systems for roof penetrations.
2. Description of Related Art
Flashing is commonly used on roofs at locations where the watertight integrity of the roof is compromised by a penetration, such as a pipe or other penetrating structure. Flashing typically comprises a structure installed in surrounding relation with the penetrating structure to prevent rain water from running down the outside of the penetrating structure and into the building. Plumbing vent pipes and electrical conduits are among the most common penetrating structures.
It has been found that lead provides a particularly suitable material for use in forming flashing structures since lead is pliable and can therefore be easily formed to fit over and around roof penetrating structures while conforming to the roof shape and slope. Lead flashing for a pipe typically includes a base formed from a flat sheet defining a circular hole with a normally projecting hollow cylindrical portion, commonly referred to as the “stack,” projecting therefrom. The flashing is typically installed over the pipe such that the base engages a portion of the roof deck with the cylindrical portion in surrounding relation with the pipe. While this configuration is generally suitable for non-metal roofs, the use of lead flashing with metal roof decks has been avoided due largely to increased corrosion resulting from possible electrolytic reactions between dissimilar metals, as well as difficulty in forming a watertight seal between a metal roof deck and a lead flashing base.
In addition, other metallic materials have been used to form flashing. For example, U.S. Pat. No. 5,970,667, issued to Thaler, discloses a split stainless steel flashing system. The flashing consists of two semi-cylindrical sections joined together by clips and resiliently compressible gasket.
The prior art further reveals a number of attempts directed to providing flashing systems fabricated from non-metallic materials in attempts to overcome the above-referenced disadvantages present with the use of metallic materials. For example, U.S. Pat. No. 5,176,408, issued to Pedersen, discloses a seal device fabricated from resilient deformable material for providing a weather seal between a pipe and a surface, such as a roof of a building, through which the pipe extends. The seal device has an apertured base member of resilient material with one end in contact with the roof and the opposite end with an aperture through which the pipe extends. U.S. Pat. No. 5,588,267, issued to Rodriguez, discloses conical roof flashing formed of an elastomeric material, or alternatively made out of a metal base with an elastomeric collar attached to the base.
U.S. Pat. No. 6,279,272, issued to Nill, Jr., discloses a vent pipe flashing system includes a lower flange, a resilient boot portion and a matching sleeve portion. Nill Jr. contemplates fabricating the lower flange of either plastic or metal. A resilient boot, formed of plastic or rubber, is used to connect the lower flange to a sleeve, fabricated from metal or plastic, with a diameter large enough to slide over the vent pipe. Nill Jr. further discloses components that are color matched, and made available in a variety of sizes to fit different size vent pipes.
Finally, U.S. Patent Application Publication No. 2002/0096242, to Wasitis, discloses a penetration pocket assembly for sealing the joint between a membrane covering a roof structure and an element projecting therethrough. The Wasitis assembly includes a rigid ring placed inside a polymeric boot that is equipped with an upper and lower flange. The ring is positioned so that an upper edge fits into the boot upper flange. The ring/boot assembly is then located on the membrane surrounding the projecting element. The ring is sealed to the membrane with an adhesive and a pourable waterproof sealant fills the area within the ring, bonding to the inside surface of the ring, the boot upper flange, the exterior surface of the projecting element, and the membrane.
While the above-referenced flashing systems appear somewhat useful when used in the applications for which they have been designed, there remains a need for improved flashing systems. More particularly, there exists a need for flashing systems specifically designed for use with metal roofs, and color matching flashing systems for use with roofs of various colors. There further exists a need for improved flashing systems for use with non-metal roof systems.